Technical specifications
A.12 Analog signal boards (SBs)
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
961
Table A- 235 Resistance
Normal range
accuracy
@ 25 °C
Normal range
accuracy
-20 °C to 60 °C
1
Resistance values above the over-range maximum value are reported as 32767.
Note
The module reports 32767 on any activated channel with no sensor connected. If open wire
detection is also enabled, the module flashes the appropriate red LEDs.
y will be achieved for the 10 Ω RTD ranges if 4 wire connections are used.
The resistance of the connection wires in 2 wire mode will cause an error in the sensor
reading and therefore accuracy is not guaranteed.
Table A- 236 Noise reduction and update times for the RTD modules
Rejection frequency
selection
4-/2-wire, 1-channel module
Update time (seconds)
3-wire, 1-channel module
Update time (seconds)
1
10 Hz (100 ms) 100 ms 0.306 0.611
To maintain module resolution and accuracy when the 400 Hz filter is selected, the integration time is 10 ms. This
selection also rejects 100 Hz and 200 Hz noise.
is applied, the module performs internal calibration for the analog-to-digital
converter. During this time the module reports a value of 32767 on each channel until valid
data is available on that channel. Your user program may need to allow for this init
ialization
time. Because the configuration of the module can vary the length of the initialization time,
you should verify the behavior or the module in your configuration. If required, you can
include logic in your user program to accommodate the initiali
zation time of the module.
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